Telescopic ladders



DeC- 13, 1956 A. J. TWILLY 3,291,258

TELESCOPIC LADDERS Filed Nov. 24, 1964 4 Sheets-Sheet l INv'ENf/Ula.

. ARCH/5 rf ruf/MEX Dec' 13, 1966 A.J.TW1LLEY TELESCOPIC LADDERS 4Sheets-Sheet INVENTOR.

6o E'fgawwp Filed Nov. 24, 1964 Dec. 13, 1966 A.J. TWILLEY 3,293,258

TELESCOPIC LADDERS Filed Nov. 24, 1964 4 Sheets-Sheet S Dac. i3, l966 A,J. TWILLEY 3,29L258 TELESCOPI C LADDERS Filed NOV. 24, 1964 4Sheets-Sheet 4 F W 4Z l 44 t@ J0 i /Z if A r raw/yf United States Patent3,291,258 TELESCOPIC LADDERS Archie J. Twiiley, 2280 Viewmont Way W.,Seattle, Wash.; Ruth I. Twilley, executrix of said Archie J. Twilley,deceased Filed ov. 24, 1964, Ser. No. 413,524 18 Claims. (Cl. 182-211)The present invention relates to ladders, and more particularly totelescopic extension and stepladders which are shallow or thin as wellas short when retracted, making them easy to handle, and capable ofbeing stored in small spaces, during periods of nonuse.

Known conventional extension ladders are composed of two or more laddersections in which each ladder section lies substantially whollyoutwardly of the adjacent ladder section when the ladder is retracted.Essentially, the depth dimension or thickness of a retractedconventional extension ladder is substantially equal to the combineddepths of the stiles of each of its sections. Examples of extensionladders of this type are disclosed by the following U.S. patents: Hummel2,147,370; Pearl 2,760,706; and Larson 2,957,543.

By way of typical example, in a five section extension ladder of theconventional type, wherein the average depth of the stiles is aboutthree and one-half inches, the thickness of the retracted ladder wouldbe about fifteen to seventeen and one-half inches. In contrast, a vesection extension ladder constructed according to the present invention,having the same average stile depth (i.e. about three and one-halfinches), would have a retracted depth of only about six inches.

Accordingly, a principal object of the present invention is to provide amultisectional extension ladder in which the stiles or side members ofthe intermediate and top sections are successively telescopicallymovable into a substantially wholly contained position within the stilesor side members of the bottom section, such that the retracted thicknessof the ladder substantially equals the depth of the stiles of the bottomsection.

The stiles of ladders according to the present invention are of inwardlyopening channel configuration. They are composed of relatively thinpanel portions. When the ladder is retracted the panel portions of eachstile extend in juxtaposition with similar panel portions of theadjacent stile of the adjoining ladder section (r sections). In essence,the relatively thin depth characteristic of ladders constructedaccording to the present invention can be attributed to the uniquedesign and judicious arrangement of the stile panels, the arrangement ofthe rungs relative to such panels, and the manner of attachment of therungs to the stiles.

Extension ladders according to the present invention constituteimprovements over the extension ladders disclosed in the aforementionedprior patents, and also constitute improvements over the ladderdisclosed in Hofele, U.S. Patent No. 244,059. The Hofele ladder is ofthe telescopic type, but the lower and intermediate ladder sections areof what may be termed a box construction. Each such section comprisesfour corner posts interconnected at the sides and along the front andback by rungs. A tier of short rungs and a series of cross bracesinterconnect each side pair of posts. Two tiers of longer rungs, one atthe front and one at the back, interconnect the two side assemblies. Thebottom section and each intermediate section in effect boxes in thesection above it, and the retracted ladder possesses a relatively largedepth dimension.

It is a further object of this invention to provide an improved ladderwhich may serve both as a stepladder and as an extension ladder, whichis capable of being easily converted from one type of ladder to theother, with but a minimum of effort, and which functions ediciently ineither capacity.

Another object of this invention is to provide a ladder of theabove-described character which is constructed to withstand a relativelyheavy loading, but which at the same time is relatively light in weightand can be easily handled.

A still further object of this invention is to provide a ladder of theabove-described type which is relatively simple in construction and canbe economically manufactured.

These and other features and characteristics of extension andstepladders according to the present invention will be apparent from thefollowing description and accompanying illustration of typicalembodiments thereof.

Reference will now be made to the drawing wherein like letters andnumerals refer to like parts, wherein the gures are approximately toscale, and wherein:

FIG. 1 is a perspective view of a retracted five-section extensionladder constructed according to the present invention, such View showingthe relatively thin profile of such ladder when the same is retracted;

FIG. 2 is a cross-sectional View taken through the stiles at one side ofthe retracted ladder, with the opposite stiles and parts of the rungsomitted, such View being taken substantially along line 2 2 of FIG. l,and showing the nesting arrangement of each relative upper stile in thestile below it, and the relative arrangement of the rungs to each otherand to the stiles;

FIG. 3 is a perspective view of the ladder of FIGS. l and 2, such viewshowing the ladder dismantled and the several sections standing apartfrom one another;

FIG. 4 is an enlarged scale perspective view of a preferred form offitting for use in securing the rungs to the stiles, such View showingthe fitting attached to a panel portion of a stile, and an end portionof a rung in spaced relationship with such fitting;

FIG. 5 is a view similar to FIG. 4, but showing the end portion of therung positioned over and crimped onto the dowel portion of the tting;

FIG. 6 is a fragmentary cross-sectional View taken through overlappingportions of the stiles at one side of adjoining ladder sections of theladder of FIGS. 1-3 when the same is extended, such view showing indetail a preferred form of apparatus or locking the extended laddersections together;

FIG. 7 is a view like FIG. 6, but showing the locking apparatus in areleased position;

FIG. 8 is a view similar to FIG. l, but of a second form of ladderconstructed according to the present invention, which ladder consists ofthree sections;

FIG. 9 is a view like FIG. 2, but taken through the ladder of FIG. 8,substantially along line 9-9 of FIG. 8;

FIG. 10 is a view like FIG. 3, but pertaining to the ladder of FIGS. 8and 9, such view showing that the top ladder section is divided intomajor and minor parts which are pivotally connected together, suchconstruction of the top ladder section, together with certainconstructional features of the ladder section immediately below it,making it possible to convert the ladder from an extension ladder to astepladder;

FIG. ll is a fragmentary View of the upper portion of the ladder ofFIGS. 8-l0 when the same is standing in the form of a stepladder, suchview showing the two positions of a brace member which is employed whenthe ladder is used in a stepladder capacity;

FIG. l2 is a fragmentary side elevational view taken in the overlappingregion of the stiles of adjoining ladder sections, such view showing amodified form of means for locking the ladder sections together, suchmeans ncluding a hook that in FIG. 12 is shown in a disengaged position;

FIG. 13 is a view like FIG. 12, but showing the hook that is pivotallyattached to the relatively upper section being engaged or hooked over arung of the relatively lower section; and

FIG. 14 is a view like FIGS. 12 and 13, but showing another position ofthe locking mechanism.

Referring more specifically to the drawing, FIGS. 1-7 relate to atypical extension ladder constructed according to the present invention.Such ladder 10 is shown in FIGS. 1, 2 and 5 to comprise five laddersections, designated from top to bottom 12, 14, 16, 18 and 20. Eachladder section comprises a laterally spaced pair of stiles or uprights,and a single tier of rungs R interconnecting between them. The stiles ofat least the bottom and intermediate sections are inwardly openingchannels formed of a plurality of panel portions. Commencing at the top,the stiles of each ladder section are telescopically received in theStiles of the section immediately below it. When the ladder is retracted(FIGS. l and 2) the stiles of the intermediate and top ladder sectionsare substantially wholly contained in (or nested in) the stiles of thebottom ladder section. The ladder sections will now be individuallydescribed.

The rungs R of the top section 12 substantially abut at their ends theweb portions 22 of the stiles of such section to which the rungs R \areperpendicularly related. Side flanges 24, 26 are formed integral withand extend inwardly from the longitudinally extending front and rearedges of the web portions 22. Stiffening lips 28, 30 are formed integralwith and extend inwardly from the side flanges 24, 26.

The stiles of ladder section 14 include `a web 32, a pair of side anges34, 36, a stifening lip 38, and a rung mounting and stiffening ange 40,all of which are preferably planar, as illustrated.

The stiles of ladder sections 16 each comprise a web 42, side flanges44, 46, a stilening lip 48, \and a rung mounting and stiffening ilange50.

In somewhat similar fashion, the stiles of ladder section 18 eachcomprises a web 52, side anges 54, 56, a stiiening lip 58, and a rungmounting and stiflening flange 60.

The stiles of bottom section 18 each include a web 62, side flanges 64,66, a stilfening lip 68, and a rung mounting and stiffening flange 70.

As shown by FIG. 2, the webs 22, 32, 42, 52, 62 extend in closely spacedparallelism. The side flanges 24, 34, 44, 54, 64, also extend in closelyspaced parallelism, and are each shown to be right angularly related toits web. As also shown by FIG. 2, side anges 26, 36, 46, 56, 66 extendin closely spaced parallelism, and are each right angularly related toits web.

The stilening lips 28, 38, 48, 58, extend in closely spaced parallelism,and together with stiffening lips 30 and 68 are preferably arranged toextend in Widely spaced parallelism with the webs 22, 32, 42, 52, 62,and are each preferably right Aangularly related to the side llange fromwhich it projects.

Each rung mounting and stiifening flange 40 extends inwardly asubstantial distance from the side flange 36 to which it is attached,and terminates closely adjacent the rungs R of ladder section 12. Eachrung mounting and stiifening flange 50 extends inwardly from the sideange 46 to which it is attached a much lesser amount, and terminatesclosely adjacent the rungs R of ladder section 14. As clearlyillustrated, the flanges 50 are situated inboardly of the anges 40,resulting in the rungs R of ladder section 16 being shorter in lengththan the rungs R of the ladder section 14. Since the rungs R of laddersection 12 are attached to the rungs 22 of the stiles of such section,they are longer than the rungs R of ladder section 14.

The anges 60, 70 both project outwardly from the side flanges to whichthey are integrally attached, but in opposite directions. The rungs R ofladder section 18 are in close parallelism with the rungs R of laddersection 16, and the rungs R of ladder section 20 are separated from therungs R of ladder section 12 by the nested group of side tlanges 24, 34,44, 54 and stiffening lips 28, 38, 48, 58.

As will be readily appreciated, it is the judicious placement andarrangement of the rung mounting and stiftening flanges 40, 50, 60, 70which make possible the close spacing of the tiers of rungs R. Thistogether with the nested arrangement of the stiles of the intermediateand top ladder sections in succession within the stiles of the bottomsection 20 is responsible for the relatively shallow depth of the ladder10 when it is retracted.

By way of typical example, and for the purpose of illustrating thes-hallow depth characteristic of ladders constructed according to thepresent invention, in a ve section ladder of the type illustrated -byFIGS. 1-7, the depth dimension of the stiles for bottom ladder section20 (i.e. the width of the web 62) may be about four and one-half inches(4l/2") and the rung depth or thickness about three quarters of an inch(34). This gives the ladder when retracted a total dept-h of`approximately six inches (6). This dimension is the sum of the depth(4l/2") of the stiles of section 20 and the thickness (1%1 each) of therungs of sections 18, 20 (FIG. 2) The ladder sections may measureapproximately four feet (4') each in length. Taking the necessaryoverlap between sections into consideration, such ladder may be adaptedto be extended out to a length of about sixteen feet (16').

As clearly shown by FIG. 1, the retracted ladder makes a compact packageand may be easily carried or stored in the trunk space or the back seatof most modern automobiles. Owing to this capability, the ladderillustrated by FIGS. 1-7 may be appropriately termed a trunk ladder.

A typical manner of attaching the rungs R of ladder section 12 to thewebs 22 of such section, and the rungs R of ladder sections 14, 16, 18,20 to the rung mounting and stiften-ing flanges 40, 50, `60, 70,respectively, of such sections, is shown by FIGS. 3 and 4. In suchfigures the rungs R are shown to be tubular. The connector 72 is shownto include a thin relatively at base 74, anda dowel 76 projectinginwardly (relative to the center of the ladder 10) from said base 74.The base 74 is riveted or otherwise suitably attached to the web orilange onto which it is to be anchored. The external configuration ofthe dowel 76 is substantially Iidentical to the internal configurationof the rung R. Preferably, the dowel 76 is made to be tight tting in therung R, so that some force is required to drive the two together. Thedowel 76 is formed to include at least one recess 78, and when the rungR is in place, it is crimped in the area of each recess 78 (FIG. 5) forthe purpose of securing the lrung R on the dowel 76.

As shown by FIGS. 1 and 3, a combined pole bracket land brace 80 may belocated at the upper end of the upper ladder section 12. The 'brace 80is shown to consist of a straight member 82 which at its ends overlapsand is secured to the upper end portions of side anges 26. The upper endportions of stitfening lips 3) are cut away to make room for the endportions of straight member 82. The brace 80 lalso includes a trihedralmember 84 which is attached lat its ends to the 4upper end portions ofside flanges 24. The upper end portions of strengthening l-ips 28 arealso cut away to make room for the end portions of rmember 84. A rivet86 or the like secures the midportion of member 82 to the midportion ofmember 84. As will be readily appreciated, when the ladder is to be usedagainst a telephone pole, tree, or the like, the trihedral member 84rests against the curved surface of such object, giving the ladderbetter than a point support at its upper end.

As also shown by FIGS. 1 and 3, the lower ends of the stiles for thelower ladder section 20 may be provided with support feet 88. AnL-shaped member 90 is shown to be attached to the lower end portion ofeach stile of ladder section 20, giving such stiles a box-likecrosssection at such location. The support feet comprise a pair oflaterally spaced, triangular side plates and a bottom platei-nterconnecting the base portions of said side plates. The upper endsof the side plates are pivotally connected to the lower end portions ofthe stiles for ladder section 20, preferably by a pin extending throughthe webs 62 and the L-shaped members 90. A ground engaging pad ofrubber, knurled aluminum, etc. may be secured to each bottom plate.

A preferred ymechanism for locking the lladder sections together in anextended position will now be described.

FIG. 1 shows that each relatively upper section extends a little abovethe upper terminal of the ladder section immediately below it. A 1handreleasable mechanism 92 for locking together ladder sections 12 land 14when the ladder is extended is shown to be located in the upperextension of the Stiles for ladder section 14. A like mechanism 94 islocated in the upper extension of ladder section 16. Lock mechanism 94serves to lock together ladder sections 14 and 16 when the ladder isextended. The mechanism for locking together ladder sections 16 and 18is located in the upper extension of the stiles for ladder section 18,and is designated 96 in FIGS. l and 3. The loc-k mechanism for lockingtogether ladder sections 18 and 20 is positioned on the side tlanges 66of the Stiles of ladder section 20, and is designated 98 in the drawing.

The ladder is extended by pulling each relatively upper section out fromits nested position within the section below it. As the top section 12is moved relatively upwardly, openings 1110 in the webs 22 of the Stilesof such top section 12 are moved into a position wherein they areengaged by a locking plug or detent forming a part of the lockingmechanisms 92. The same is true with respect to each adjoining pair ofladder sections below ladder section 12.

FIGS. 6 and 7 are fragmentary sectional views taken through the stilesof ladder sections 14 a-nd 16. Referring first to FIG. 6, the lockingmechanism 94, which is identical in construction to locking mechanisms92, 96, 98, is shown to consist of a flat, elongated bar spring 102attached at one end to the web 42 by a -rivet 104 o-r the like. A detent106 is located slightly inwardly from the opposite end of spring 1112.An opening is formed in web 42, and the detent 106 extends through suchopening. Another opening 168 (FIG. 3) is formed in the webs 32 of laddersection 14. The openings 1G18 are in the path of the respective plugelements 1116, and when ladder sectio-ns 14 and 16 are moved relativelyapart as the ladder is extended, the openings and the detents 166 areymoved relatively together, wit-h the detents 106 eventually enteringinto the openings 10S to be engaged thereby and prevent further movementof the ladder sections. FIG. 6 illustrates the lock position of thelocking mechanism 94, wherein the detent 166 is engaged by an opening108. A keirf or slot 110 may be cut in the upper portion o'f the detent166. This slot 110 engages the lportion of panel 32 that immediatelyborders the opening 108 on the upper side thereof.

The end of spring element 102 opposite the pin 104 is curled outwardlyso as to form a handle 112. The locking mechanism 94 is unlocked by theuser grasping the handle 112 and pulling the detent 106 out ofengagement by the opening 108. This allows the ladder section 14 to betelescoped into, or to be completely removed out from, the laddersection 16. FIG. 7 shows the locking mechanism 94 in an unlockedposition. Spring member 1116 may be pivotally attached to the panel 42by the pin 104 so that the detent 106 may be pivoted out of alignmentwith the opening in panel 42 when it is desired that the lockingmechanism not function.

FIGS. 8-14 relate to a modified form of telescopic ladder according tothe present invention. Such ladder, designated 114, is adapted to beboth an extension ladder and a stepladder. Ladder 114 is shown tocomprise three ladder sections, designated (from top to bottom) 116,118, and 1241. Ladder sections 116, 118, are essentially identical inconstruction with latter sections 12, 14, 16, respectively of the laddershown by FIGS. l-7, except that they are longer. Due to this substantialidentity in construction, the reference character designation given thepanel portion of the stiles of the ladder shown by FIGS. 1 7 are alsoused in conjunction with the ladder shown by FIGS. 8-14.

FIGS. 8-14 also disclose a modified form of mechanism for lockingadjacent ladder sections together when the ladder is extended. FIGS.1214 present a succession of fragmented views taken in the vicinity ofthe locking mechanism for locking ladder sections 116 and 118 together.Such mechanism comprises a hook 122 that is pivotally connected to web22 at a point below the lowermost rung R of ladder section 116, thepivot point being designated 124 in the drawing. The hook 124 extendsupwardly and inwardly from the pivotal connection 124 to contain thesaid lowermost rung R of ladder section 116 in its open throat area. Aspring 126 is attached at its upper end to hook 122 at point 128. Thespring curves rst upwardly and then downwardly from point 128 ininverted U fashion. The spring 126 takes a wrap around pivot pin 124 andthen extends along and is secured to an arm 13). Arm 131i, which is alsomounted for pivotal movement by pin 124, will be hereinafter describedin greater detail. The upper inboard edge of hook 124 is convex in shapeand serves as a cam surface when the ladder sections 116, 118 are beingmoved relatively together from the position illustrated by `solid linesin FIG. l2. Referring to FIG. 12, as the rung R attached to ange 32moves relatively downwardly and closer tothe rung R attached to ange 22,such former rung R contacts the cam surface 134 on hook 122, and causeshook 122 to swing into the position depicted by broken lines in FIG'.12. As soon as the upper portion of hook 122 clears the rung R attachedto ange 32, the hook 122 is returned to the solid line position by thespring 126, at which time the hook 122 engages both of the rungs R, asis illustrated by FIG. 13. In referring to FIG. 13, it is to beremembered that ladder section 118 is the relatively lower section, andbetween the two sections 116, 11S, it is the relatively upper section116 that tends to slide downwardly and must be held. Such downwardmovement of ladder section 116 is prevented by the fact that hook 122extends over and engages the rung R of ladder section 118. It canclearly be seen that ladder section 116 cannot move downwardly as longas the rung R of ladder section 11S is in the way of the upper portionof hook 122. Of course, when it is desired that the two ladder sections116, 118 be moved relatively together, the hook 122 can be moved by handto a position wherein it no longer engages the rung R aixed to laddersection 118.

As also shown by FIG. 13, when ladder section 118 is moved relativelydownwardly, or ladder section 116 is moved relatively upwardly, from theposition shown by solid lines in FIG. 13, the rung R attached to panel32 strikes arm 13d and pivotally moves it against the force of the lowerportion of spring 126 into the position shown by broken lines in FIG.13, wherein it is out of the way and does not prevent further relativemovement of the rung R attached to panel 32.

Referring now to FIG. 14, when the ladder sections 116, 118 are moved inthe opposite sense, i.e. ladder section 118 is moved relatively upwardlyand ladder section 116 is moved relatively downwardly, and the rung Rattached to panel 32 is initially below the arm 130, such arm 130 isrotated clockwise, as pictured, by said rung R. The arm 136 movesagainst a shoulder 136 on hook 122 and in that manner pushes the hook122, causing it also to swing in the clockwise direction, as pictured inFIG. 14. By the time that the rung R has cleared the upper end of arm130, it will be adjacent and able to make contact with the cam surface134 so that when the arm 130 snaps back into the position shown by solidlines in FIG. 13, the hook 122 will not immediately follow it. Thisenables the rung R of ladder section 118 to move relatively upwardlywithout being engaged by the open throat area of the hook 122.

Referring now to FIG. 10, ladder section 116 is shown to be divided intotwo parts, which hereinafter will be termed its major and minor parts.The major part 140 is pivotally connected to the minor part 142 by meanscomposed of a pair of substantially V-shaped plates 144, and pivot pins146, 148 pivotally connecting the upper and lower end portions of theplates 144 to the major and minor parts 140, 142 of the ladder section.When the ladder 114 is used as an extension ladder, the minor part 142,the plates 144, and the lower end portions of the major part 140 arehoused in the upper portion of ladder section 118, and the articulatedconstruction of ladder section 116 plays no part in the function of theladder.

Referring now to FIG. 11, a block 150 serving as a stop member, issecured to the inside surface of webs 22. A similar block or stop member152 is secured to the outboard surface of panels 40. The blocks 150, 152prevent the removal of the top ladder section 116 entirely out fromengagement by the intermediate ladder section 118, but do allow themajor part 140 of said ladder section 116 to be removed from engagementby the ladder section 118. The major section 140 may be then pivotallymoved into a position wherein it makes an acute angle with theintermediate and bottom ladder sections 118, 120.

A brace 154 is pivotally connected at its lower end to ange 40 of eachstile of ladder section 118 (FIG. 10). Each brace 154 is straightthroughout the greater portion of its length, but angles to one side ofits upper end. A pin 156 is provided at the upper end of each brace 154.When the braces 154 are not being used, they occupy the position shownby broken lines in FIG. l1, and by solid lines in FIG. 10. In suchposition, the pin 156 is engaged behind a lip 158 that extends in aplane that is generally parallel to the general plane of the rungs R.When the braces 154 are to be used, they are grasped at their upper endsand pulled slightly inwardly toward the center of the ladder section 118until the pin 156 clears the lip 158. The braces 154 are then swungdownwardly into a near horizontal position, and the pin 156 is engagedinto a keyhole opening 160 formed in web 22 of the stiles for the laddersection 116 in its major part. Preferably, the pin 156 has an enlargedhead. The enlarged head is inserted into the large circular portion ofthe keyhole opening 160 and then the brace is moved downwardly so thatthe shank portion of pin 156 is engaged by the slot portion of thekeyhole opening 160. The enlarged head is wider than the slot and thuscannot pass laterally through the slot.

If ladder 114 is used as a stepladder on uneven ground, or on a slightgrade, v'intermediate ladder section 118 may be telescopically moved aslight distance out from its position in bottom ladder section 120 inorder to make its side of the stepladder longer. This longer side maythen be set in the down-hill position when the ladder is being used on aslight grade, or in the low spot when the ladder is being used on unevenground.

In FIGS. 8 and 10, the converted U-shaped members 162 provided at thetop of ladder section 116 are rub rails. They are rubber covered orsmooth surfaced and are provided so that the ladder will not mar thesurface against which it leads.

The ladders shown by FIGS. 1-7 and FIGS. 8-14 are but two embodiments oftelescopic ladders according to the present invention. As will bereadily appreciated, the basic principles involved in the presentinvention may be found in ladders that differ substantially inconstruction from the ladders illustrated in the drawing. For example,the stepladder principles may be applied to the tive section ladderillustrated by FIGS. 1-7. Also, it may be desirable to make the ladderin only two or four sections. The rungs R may be made round or in someother shape differing from what is illustrated. Also, it may bedesirable to give the stiles, or at least the web portions of thestiles, a somewhat rounded lateral shape, rather than making them planaras illustrated. The locking mechanisms that are illustrated anddescribed are preferred mechanisms for performing the locking functionand constitute a part of the present invention. However, it is to beunderstood that other types of locking mechanisms may be satisfactorilyused.

Preferably all parts of the ladders constructed according to theinvention, except for the locking mechanism and the fasteners, pivotpins, etc., are preferably constructed from aluminum. The stiles may bebrake formed, extruded or cast. Extrusion is preferred. The tubular onesare preferably also extruded. Of course, it is to be understood thatmaterials other than aluminum may be used, and the invention is not tobe limited to a particular material, or to a particular mode ofmanufacture, unless a claim is so limited.

From the foregoing, further variations, adaptations and modificationswith respect to telescopic extension and stepladders according to thepresent invention can be evolved by those skilled in the art to whichthe invention is addressed, within the scope of the following claims.

What is claimed is:

1. A telescopic extension ladder comprising a top section, a bottomsection, and at least one intermediate section, each of said sectionsincluding a pair of parallel, laterally spaced stiles and a single tierof rungs extending between and interconnecting said stiles, with thestiles of the top and intermediate sections being telescopicallyreceived in the stiles of said bottom section, with the tiers of rungsof the top and intermediate sections being in parallelism with eachother and with the tier of rungs of the bottom section, with the s-tilesof the bottom and intermediate sections being of channel form and eachcomprising a web, a pair of side flanges formed integral with andextending inwardly from the edges of said web, a rung mounting flangeformed integral with and extending inwardly from one of said sideflanges and extending in spaced parallelism with said webs, and astitening lip formed integral with and extending inwardly from the otherone of said side flanges, and also extending in spaced parallelism withsaid webs, with the stiles of the top section each comprising a web thatextends in closely spaced parallelism with the webs of the stiles ofsaid bottom and intermediate sections, with the ends of the rungs of thesaid top section being secured to the webs of that sections stiles, andwith the ends of the rungs of said intermediate and bottom sectionsbeing secured to the rung mounting flanges of the stiles of saidsections.

2. A telescopic extension ladder according to claim 1, wherein at leastthe end portions of the rungs are tubular, and the connector means forsuch rungs each comprises a thin, substantially planar mounting base, adowel secured at one end to said mounting base and extending from saidmounting base into the adjacent end of its rung, with said rung havingan end surface that substantially abuts against the face of the mountingbase, with said dowel having an exterior conguration substantiallymatching the interior configuration of the rung, with at least onerecess being formed in the dowel, and with the portion of the rung oversuch recess being crimped into the notch for the purpose of securing therung to the dowel.

3. In a telescopic extension ladder, rst and second ladder sections,each comprising a pair of laterally spaced stiles and a tier of rungsextending between and interconnecting said stiles, with the stiles ofsaid rst ladder section being telescopically received in the Stiles ofsaid Second ladder section, with the tier of rungs of Said first laddersection being generally parallel to the tier of rungs of said secondladder section, and with each of the Stiles of the first ladder sectioncomprising a plurality of relatively thin panels including a web and apair of Side anges made integral with and turning inwardly from Saidweb, and each of the Stiles of the second ladder section comprising aplurality of relatively thin panels including a web extending outwardlyadjacent the web of the adjoining Stiles of Said first ladder section, apair of side flanges made integral with and extending inwardly from theweb of such stile of the second ladder section, outwardly adjacent theanges of the adjoining stile of said first ladder Section, and a rungmounting and stiifening flange made integral with and extending inwardlyfrom one of Said Side anges of such side member of the second laddersection, with the rungs of said second section being Secured at theirends to the rung mounting and stilfening flanges of the Stiles of SaidSecond ladder Section, and means for locking said first and Secondladder sections together when the ladder is extended, Said meanscomprising an elongated relatively at and thin Spring element disposedoutwardly of, and pivotally connected at one of its ends to, one of saidpanels of at least one stile of the second ladder Section, and aninwardly projecting detent Secured to the end of Said spring elementopposite from the pivotal connection, with an opening for Such detentbeing formed in the panel portion of the stile to which the Springelement is pivotally connected, and with a Second opening being formedin the adjacent panel portion of the first ladder section, in the pathof such detent, so that when the ladder Sections are pulled relativelyapart -th'e Said detent and the said opening in the panel portion of thestile of the first ladder section are moved relatively together, and thedetent then enters into Such opening and prevents further relativemovement of the two ladder sections, Said Spring element furtherincluding handle means by which it may be grasped for the purpose ofpulling the detent out of engagement from the said opening in the saidpanel portion of the Stile of the first ladder Section, so that theladder sections may again be moved relative to each other.

4. In a telescopic ladder, first and Second ladder Sections, eachcomprising a pair of laterally spaced Stiles and a tier of rungsextending between and interconnecting Said Stiles, with the Stiles ofSaid first ladder section being telescopically received in the Stiles ofsaid Second ladder section, with the tier of rungs of Said first laddersection being generally parallel to the tier of rungs of said secondlad-der section, and with each of the Stiles of the first ladder Sectioncomprising a web and a pair of Side fianges formed integral with andturning inwardly Lfrom said web, Iand ea-ch of the Stiles of the second.f

ladder section comprising a web extending outwardly adjacent the web ofthe adjoining stile of Said first ladder Section, a pair -of Side angesforme-d integral with and extending inwardly from the web of Such Stileof the second ladder section, outwardly adjacent the side flanges of theadjoining Stile olf said first ladder section, and a rung mounting andstiifening flange formed integral with and extending inwardly from oneof Said side flanges of Such stile of the Second ladder Section, withthe rungs of Said first ladder section being secured at their ends tothe webs of the Stiles of :said first ladder section, and with the rungsof said Second ladder Section being secured at their ends to the saidrung mounting and stiffening anges of the Stiles of said second laddersection.

5. A telescopic ladder according to claim 4, further including meansf-or locking adjacent ladder Sections together when extended, said meanscomprising an elongated, relatively fl-at and t-hin spring elementdisposed outwardly of, and connected at one of its ends to, at least onestile of `each relatively lower ladder Section, and an inwardlyprojecting detent Secured to the end of said spring element oppositefrom the connection, with an opening for such detent being formed in theStile to which the spring member its connected, and with a Secondopening being formed in the adjacent stile of the other ladder section,in the path of such detent, so that when the ladder sections are pulledrelatively apart the Said detent and said second opening are movedrelatively together, and the detent can enter into such opening andprevent further relative movement of the two ladder sections, saidSpring elements further including handle means by which it may begrasped for the purpose of pulling the detent out of engagement fromsaid Second opening, for permitting the ladder sections to be movedrelative to each other.

6. The combination of claim 4, further including a third ladder sectionhaving a pair of laterally spaced Stiles and a tier of rungs extendingbetween and interconnecting Said Stiles, with the Stiles of Said secondladder Section being telescopically received in the Stiles of said thirdladder Section, each Stile of the third ladder section compriSi-n'g aweb extending -outwardly yadjacent the web of the adjoining Stile ofsaid second ladder section, a pair of Side flanges formed integral withand extending inwardly from the web of Such stile of the third ladderSec tion, outwardly adjacent the side flanges of the adjoining stile ofsaid second ladder section, and a rung mounting and stiffening flangeformed integral with and extending inwardly from one of said fianges ofsuch stile of the third ladder sect-ion, with the rungs of Said thirdladder section being secured at their ends to the rung mounting andstiffening flanges of the Stiles of said third ladder section.

7. The combination of claim 6, further including a fourth ladder Sectionlhaving a pair of Ilaterally spaced Stiles and a tier of rungs extendingbetween and interconnecting Said Stiles, with the Stiles olf Said thirdladder Section being telescopically received in the 4Stiles of saidfourth ladder section, each Stile of the fourth ladder Sectioncomprising a web extending outwardly adjacent the web of the adjoiningstile of said third ladder section, a pair of Side anges formed integralwith and extending inwardly from the web of such Stile of the fourthladder section, outwardly adjacent the side flanges of the adjoiningStile of Sa-id third ladder section, and a rung mounting and Stiffeningflanges for-med integral with and extending 'outwardly from the sidefian'ge of such stile of the fourth ladder Section that is locatedclosest to the rung mounting and stiffening flange olf the adjoiningstile of Said third ladder section, with the rungs o-f said fourthladder section being secured at their ends to the rung mounting andstiffening flanges of the Stiles of Said fourth ladder section.

8. The combination of claim '7, further including a fifth ladder sectionhaving a pair of laterally spaced stilles an-d a tier of rungs extendingbetween and interconnecting Said Stiles, with the Stiles o-f said fourthladder section being telescopically received in the Stiles of Said fifthladder section, each Said stile of the fth ladder section comprising aweb extending outwardly adjacent the web Iof the adjoining Stile of Saidfourth ladder section, a pair olf side anges formed integral with andextending inwardly from the web of such Stile of the fifth laddersection, outwardly adjacent the side flanges of the adjoining Stile ofsaid fourth ladder Section, and a rung mounting and stiffening flangeformed integral with and extending outwardly from the side flange ofsuch St-ile of the fifth ladder section that is the furtherest removedfrom the rung mounting and stiffening fiange of said fourth laddersection, with the rungs of said fifth ladder sec-tion being Secured attheir ends to the rung mounting and Stiffening flanges of the Sidemembers of said fifth ladder Section.

9. In a telescopic ladder, first and second ladder Sections, eachcomprising a pair of laterally spaced Stiles and a tier of rungsextending between and interconnecting said stiles, with each of thestiles of the first ladder section comprising a web, a pair of sideflanges formed integral with and turning inwardly from said web, and ar-ung mounting and stifiening llange formed integral with and extendinginwardly from one of said side flanges, substantially parallel to theweb of such stiles and substantially perpendicularly to the rung axes,with the rungs of said rst ladder section being secure-d at their endsto the said rung mounting and stifening flanges, and each stile of thesecond ladder section comprising a web extending outwardly adjacent, andsubstantially parallel to, the web of the adjoining stile of said firstladder section, a pair of side flanges formed with and extendinginwardly from the web olf such stile of the second ladder section,outwa-rdly adjacent and substantially parallel to the side llanges ofthe adjoining stile of said first ladder section, and a rung mountingand stiffening llange formed integral with rand extending inwardly fromthe side flange of such stile of the second ladder section that isclosest to the rung mounting and stilening flange of the adjacent stileof said irst ladder section, with the rungs of said second laddersection being secured at their ends to the said rung mounting andstiffening llanges of the stiles of said second ladder section.

10. A telescopic ladder according to claim 9, further including meansfor locking adjacent ladder sections together when extended, said meanscomprising an elongated relatively flat and thin spring element disposedoutwardly of, and connected at one of its ends to, at least one stile ofeach relatively lower ladder section, and an inwardly projecting detentsecured to the end of said spring element opposite from vthe connection,with an opening lfor such detent being formed in the stile to which thespring member is connected, and with a second opening being formed inthe adjacent stile of the other ladder section, in the path of suchdetent, so that when the ladder sections are pulled relatively apart thesaid detent and said second opening are moved relatively together, `andthe detent can enter into such opening and prevent further relativemovement of the two ladder sections, said spring elements furtherincluding handle means by which it may be grasped for the purpose ofpulling the detent out of engagement from said second opening, forpermitting the ladder sections to be moved relative to eachother.

11. In a telescopic ladder, first 4and second ladder sections, eachcomprising a pair of laterally spaced stiles and a tier of rungsextending between and interconnecting said stiles, with each of thestiles of the rst ladder section comprising a web, a pair of sideflanges formed integral with and turning inwardly from said web, and arung mounting and stiffening flange formed integral with and extendinginwardly lfrom `one of said side flanges, substantially parallel to theweb of such stile, and substantially perpendicularly to the rung axes,with the rungs of said first ladder section being secured at their endsto the said rung mounting and stiffening llanges, and each stile of thesecond ladder section comprising a web extending outwardly adjacent, andsubstantially parallel to, the web of the adjoining stile of said firstladder section, a pair of side flanges formed with and extendinginwardly from the web of such stile of the second ladder section,outwardly adjacent and `substantially parallel to the side flanges ofIthe adjoining stile of said lirst ladder section, and a rung mountingand stil-lening flange formed integral with and extending outwardly fromthe side llange of such stile of the second ladder section that isclosest to the r-ung mounting and stiffening flange of the adjacentstile of said rst ladder section, substantially parallel to the web ofsaid stile of the second ladder section, and substantiallyperpendicularly to the rung axes, with the rungs of said second laddersection being secured at their ends to the said rung mounting andstiftening flanges of the stiles of said second ladder section.

12- A telescopi? ladder according to claim 11, further including meansfor locking adjacent ladder sections together when extended, said meanscomprising an elongated, relatively tlat and thin spring elementdisposed outwardly of, and connected at one of its ends to, at least onestile of each relatively lower ladder section, and an inwardlyprojecting detent secured to the end of said spring element oppositefrom the connection, with an opening for such detent being formed in thestile to which the spring member is connected, and with a second openingbeing formed in the adjacent stile of the other ladder section, in thepath of such detent, so that when the ladder sections are pulledrelatively apart theA said detent and said second opening are movedrelatively together, and the detent can enter into such opening andprevent further relative movement of the two ladder sections, saidspring elements further including handle means by which it may begrasped for the purpose of pulling the detent out of engagement fromsaid second opening, for permitting the ladder sections to be movedrelative to each other.

13. In a telescopic ladder, first and second ladder sections, eachcomprising a pair of laterally spaced stiles and a tier of rungsextending between and interconnecting said stiles, with each of thestiles of the first ladder section comprising a web, a pair of sideflanges formed integral with and turning inwardly from said web, and arung lmounting and stiflening flange formed integral with and extendingoutwardly from one of said side flanges, and each of the stiles of thesecond ladder section comprising a web extending outwardly adjacent theweb of the adjoining stile of said rst ladder section, a pair of sideflanges formed integral with and extending inwardly from the web of suchstile of the second ladder section, outwardly adjacent the side flangesof the adjoining stile of said first ladder section, such that thestiles of said first ladder section are telescopically received in thestiles of said second ladder section, and a rung mounting and stiffeningflange formed with and extending outwardly from the side llange of suchstile of the second ladder section that is the furtherest removed fromthe rung mounting and stiffening flange of the rst ladder section, withthe rungs of said first ladder section being secured at their ends tothe rung mounting and stiffening flanges of the stiles of said firstladder section, with the rungs of said second ladder section beingsecured at their ends to the said rung mounting and stiffening flangesof the stiles of said second ladder section, and with the tier of rungsof said first ladder section lbeing generally parallel to the tier ofrungs of said second ladder section.

14. A telescopic ladder according to claim 13, further including meansfor locking adjacent ladder sections together when extended, said meanscomprising an elongated, relatively flat and thin spring elementdisposed outwardly of, and connected at one of its ends to, at least onestile of each relatively lower ladder section, and an inwardlyprojecting detent secured to the end of said spring element oppositefrom the connection, with an opening for such detent being formed in thestile to which the spring member is connected, and with a second openingbeing formed in the adjacent stile of the other ladder section, in thepath of such detent, so that when the ladder sections are pulledrelatively apart the said detent and said second opening are movedrelatively together, and the detent can enter into such opening andprevent further relative movement of the .two ladder sections, saidspring elements [further including handle means by which it may begrasped for the purpose of pulling the detent out of engagement fromsaid second opening, for permitting the ladder section to be movedrelative to each other.

15. A telescopic extension ladder comprising first and second laddersections, each including a pair of laterally spa-ced stiles and a tierof rungs extending between and interconnecting said stiles, with thestiles of said second ladder section being of inwardly opening channelcon- 13 iiguration, with the stiles of said tirst ladder section beingtelescopically received in the stiles of said second ladder section, andwith the tier or rungs of said iirst ladder section being generallyparallel to the tier or rungs of said second ladder section, said firstladder section being divided longitudinally into major and minor parts,and said first ladder section including means pivotally connecting saidmajor `and minor parts together, for movement between a substantiallyaligned posit-ion and an angularly related position, stop means forpreventing the said iirst and second ladder sections from being pulledentirely apart, said stop means -comprising a stop member on said secondladder section adjacent the -upper end of one of its side members, and acomplementary stop member secured to the corresponding stile of the rstladder section, in the minor part olf such section, such stop meanspermitting the major part of the irst ladder section to be pulledcompletely out of telescopic engagement by the second ladder section,:but preventing removal of said minor part, said pivotal connectionmeans permitting movement of the major part of the first ladder sectioninto an acute angular position relative to the second ladder section,and said minor ladder part still engaged thereby, and brace meansinterconnectable between intermediate portions of said major part of thefirst ladder section and said second ladder section.

16. A telescopic ladder according to claim 15, further including meansfor locking adjacent ladder sections together when extended, said meanscomprising an elongated, relatively at and thin spring element disposedoutwardly of, and connected at one of its ends to, at least one stile ofeach yrelatively lower ladder section, and an inwardly projecting detentsecured to the end of said spring element opposite from the connection,with an opening for such detent being iformed in the stile to which thespring member is connected, and with a second opening being formed inthe adjacent stile of the other ladder section, in the path of suchdetent, so that when the ladder sections are pulled relatively apart thesaid detent and said second opening lare moved relatively together, andthe detent can enter into such opening and prevent turther relativemovement of the two ladder sections, said spring elements furtherincluding handle means by which it may be grasped for the purpose ofpulling the detent out of engagement from said second opening, forpermitting the ladder sections to be moved relative to each other.

17. A telescopic extension ladder comprising a plurality of laddersections, including at least one with a section both above and below it,each of which sections includes a pair of parallel stiles of inwardlyopening channel configuration, each said stile being composed of aplurality of relatively thin panel portions, including a web portion, apair of side anige portions :formed integral with and extending inwardlyfrom the side edges of said web portion, and a stiftening flange portionformed integral with each of said side ilange portions and extendingtherefrom in a spaced, substantially parallel relationship with the webportion, and a single tier of rungs extending between andinterconnecting said stiles, with the web and -stiiening ilange panelportions of said stiles extending in planes which are substantiallyperpendicularly rel-ated to the rung axes, .and connector meansconnecting the ends of the rungs to one of such web and stiiening panelportions, with each tier of rungs be-ing in parallelism with each othertier of rungs, with the stiles of each relatively upper ladder sectionbeing telescopically received in the stiles of the section below it,with the s-tiles of each relatively upper ladder section having an upperportion which extends upwardly a short distance above the top ends ofthe Stiles of the section below it, and means for locking adjacentladder sections together when extended, said means comprising anelongated, irelatively Hat .and thin spring element disposed outwardlyof, and connected at one olf its ends to, a panel portion of at leastone stile of each relatively lower ladder section, and an inwardlyprojecting detent secured to the end of said spring element oppositefrom the connection, with an opening for such detent [formed in saidpanel portion to which the spring member is connected, and with a secondopening being formed in the adjacent panel portion of the relativelyupper ladder section, in the path of such detent, `so that when theladder sections -are pulled relatively apart the said detent and saidsecond opening are moved relatively together, and the detent can enterinto such opening and prevent further relative movement of the twoladder sections, said spring element further including handle means bywhich it 'may be grasped for the purpose of pulling the detent out ofengagement from said second opening, for permitting the ladder sectionsto be again moved relative to each other, and with the spr-ing elementon each section which has another section both above and below itextending across, and being secured to, the web panel of its stile, inthe said upper end portion olf said stile.

18. A telescopic ladder according to claim 17, wherein each `springelement is pivotally connected to its panel portion, so that the detentcan be pivotally moved out from a position of registry with the openingin said panel portion.

References Cited by the Examiner UNITED STATES PATENTS 37,470 1/11863.Willis 182-208 294,199 2/ 1884 Cloyes 1182--204 567,814 9/ 1896`Orna'towski 182-67 1,192,387 7/191'6 Cardarelli 182-67 X 2,306,453 12/1942 Madden 182-67 FOREIGN PATENTS 1,211,973 10/ 1959 France.

524,467 `8/1940 Great Britain.

REINALDO P. MACHADO, Primary Examiner.

1. A TELESCOPIC EXTENSION LADDER COMPRISING A TOP SECTION, A BOTTOMSECTION, AND AT LEAST ONE INTERMEDIATE SECTION, EACH OF SAID SECTIONSINCLUDING A PAIR OF PARALLEL, LATERALLY SPACED STILES AND A SINGLE TIEROF RUNGS EXTENDING BETWEEN AND INTERCONNECTING SAID STILES, WITH THESTILES OF THE TOP AND INTERMEDIATE SECTIONS BEING TELESCOPICALLYRECEIVED IN THE STILES OF SAID BOTTOM SECTION, WITH THE TIERS OF RUNGSOF THE TOP AND INTERMEDIATE SECTIONS BEING IN PARALLELISM WITH EACHOTHER AND WITH THE TIER OF RUNGS OF THE BOTTOM SECTION, WITH THE STILESOF THE BOTTOM AND INTERMEDIATE SECTIONS BEING OF CHANNEL FORM AND EACHCOMPRISING A WEB, A PAIR OF SIDE FLANGES FROMED INTEGRAL WITH THEEXTENDING INWARDLY FROM THE EDGES OF SAID WEB, A RUNG MOUNTING FLANGEFORMED INTEGRAL WITH AND EXTENDING INWARDLY FROM ONE OF SID SIDE FLANGESAND EXTENDING IN SPACED PARALLELISM WITH SAID WEBS, AND A STIFFENING LIPFORMED INTEGRAL WITH AND EXTENDING INWARDLY FROM THE OTHER ONE OF SAIDSIDE FLANGES, AND ALSO EXTENDING IN SPACED PARALLELISM WITH SAID WEBS,WITH THE STILES OF THE TOP SECTION EACH COMPRISING A WEB THAT EXTENDS INCLOSELY SPACED PARALLELISM WITH THE WEBS OF THE STILES OF SAID BOTTOMAND INTERMEDIATE SECTIONS, WITH THE ENDS OF THE RUNGS OF THE SAID TOPSECTION BEING SECURED TO THE WEBS OF THAT SECTION''S STILES, AND WITHTHE ENDS OF THE RUNGS OF SAID INTERMEDIATE AND BOTTOM SECTIONS BEINGSECURED TO THE RUNG MOUNTING FLANGES OF THE STILES OF SAID SECTIONS.